ORA-15032 ORA-15040 ORA-15042 while mounting a diskgroup

 You may face these 3 error messages together if you are trying to mount an ASM diskgroup and one or more disks of this diskgroup are missing. In case of an external redundancy diskgroup, you need at least one ASM disk to be available to mount a diskgroup. For a normal redundancy diskgroup, you need at least 2 disks for the ASM diskgroup before it can be mounted. And in case of a high redundancy diskgroup, you need at least 3 disks to mount a diskgroup. After an ASM instance restart, an ASM diskgroup may not get mounted automatically if it is not fulfilling the requirements explained above.

For the following example I have a diskgroup with normal redundancy with 3 disks and it has lost one of its disks. Since this diskgroup is no more usable because of a lost disk, only option is to drop this diskgroup and then recreate. Before we can drop this diskgroup manually (provide link of next article about dropping the disk), we would need to mount this diskgroup with FORCE option because we cannot mount a diskgroup without FORCE option in such cases.

SQL> alter diskgroup crs mount; alter diskgroup crs mount * ERROR at line 1: ORA-15032: not all alterations performed ORA-15040: diskgroup is incomplete ORA-15042: ASM disk "3" is missing from group number "1" SQL> alter diskgroup crs mount force; Diskgroup altered.

 

Now we can query all the disks of this diskgroup that are either available or unavailable.

SQL> select name,path,state,header_status from v$asm_disk where group_number=0;   NAME                           PATH                                 STATE    HEADER_STATU ------------------------------ ---------------------------------------- -------- -------- CRS0                       \\.\ORCLDISKCRS0                         NORMAL   MEMBER      CRS1                       \\.\ORCLDISKCRS1                         NORMAL   MEMBER      CRS2                                                                                  NORMAL   UNKNOWN

You can try recovering the missing disk, or proceed with dropping the diskgroup and recreating it with new disks and perform recovery of the files stored on this diskgroup.